There is a continuing interest in improving the functional performance of xerographic photoreceptors. For example, it is generally desirable to reduce the post-discharge voltage of a photoreceptor and to minimize changes in its electrical characteristics during prolonged electrical cycling. There is also an impetus to extend the life of the photoreceptor in order to reduce run costs. Achieving both of these goals simultaneously has been a challenge.
By way of example, incorporation of low wear, life-extending compositions, such as protective overcoats, cross-linking polymer binders, or low surface energy additives generally results in a reduction in average charge mobility throughout the photosensitive layers. This leads to an unwanted increase in post discharge surface voltage. To combat this problem, attempts have been made to identify higher mobility charge transport molecules for both charge transport layers and overcoat layers. Thus far, the increase in average mobility has been limited due to the solubility of the hole transport molecules in the photosensitive layers.